1. Field of the Invention
The present invention relates to an improvement in an image recording apparatus for recording, with a scanning light beam modulated with an image signal, an image or a multiformat image composed of a plurality of images (e.g. a medical tomographic image using X-rays, ultrasonic light rays, or the like) on a recording sheet disposed on a drum which is rotated such that a direction perpendicular to the scanning direction of the scanning light beam is tangential to the drum.
2. Description of the Prior Art
In a conventional apparatus of the type described above, as shown in FIG. 1, recording sheets S stored in a feed magazine 2 are picked up one by one by a sheet pickup unit 3 and inserted between feed rollers 4. The sheet S is supplied to a drum 1 by the feed rollers 4 through a guide plate 5. The sheet S is driven at a constant speed by bringing it into contact with the drum 1 rotating at a predetermined speed. An image is recorded on the sheet S by laser beam scanning. A laser beam L emitted from a laser light source 6 is modulated by an optical modulator 7 and is main-scanned by a galvano mirror 8. The laser beam L is projected to record on the recording surface of the drum 1 through lens 9 and mirrors 10, 11. The recording sheet S on which the image has thus been recorded is stored in a storage magazine 14 through a guide plate 12 and exhaust rollers 13. The sheet S is then manually carried to a developer by the operator or is directly brought to the developer downstream of the convey path without being stored in the magazine 14. Then, the developer developes the image.
While the image is recorded on the sheet S disposed on the periphery of drum 1, the rear end of the sheet S must be away from the rollers 4 and the front edge of the sheet S must not be clamped between the rollers 13 in order to prevent irregular sheet feed. Assuming that the beam scanning surface including the laser beam line between the recording position on the drum 1 and the mirror 11 is a boundary, the inlet side from this boundary up to the rollers 4 must have a space corresponding to the length of the recording sheet S and the outlet side from this boundary down to the rollers 13 must also have a similar space. Thus, the feed and storage magazines 2 and 14 are opposed to each other at the two sides of the boundary. For this reason, loading/unloading operability of the magazines 2 and 14 is degraded, and the total height or length of the apparatus is increased. In addition, the optical system including the laser light source 6 must be arranged away from the operating portion of the magazines 2 and 14. Then, a complex arrangement must be adopted wherein the optical system crosses the two sides of the boundary. As a technique for winding a recording sheet S around a drum 1, although slightly different from the field of the present invention, a technique in an ink-jet printer as shown in FIG. 2 is disclosed in Japanese patent application laid-open No. 10346/1984. In this specification, a recording sheet S taken out from a feed magazine 2 is wound around the drum 1 through feed rollers 4. The sheet S is rotated with the drum 1 and is recorded by an ink-jet head 15. The recording sheet S on which an image has been recorded in this manner is exhausted by exhaust rollers 13.
In the above-mentioned apparatus, mainscanning is performed by rotation of the drum 1, and subscanning is performed by movement of the ink-jet head 15 along the drum axis. Suppose that the drum rotation mechanism shown in FIG. 2 is applied to the subscanning section shown in FIG. 1. Then a large drum section is not required since the rollers 4 and 13 can be arranged near the drum 1. Since separate rollers are used to feed and exhaust the sheet S to and from the drum, conveyance control is easy. However, in the drum rotation mechanism shown in FIG. 2, the obverse/reverse relationship of the sheet S is opposite when the sheet S is in the feed magazine 2 and in the storage magazine 14.
In case that a silver salt film having an emulsion coated on one surface is used as a recording sheet S, when the film is picked up from the magazine 2 to the drum section or when the storage magazine is loaded in a developer and the film is taken out from the storage magazine to be placed in a developing tank, the suction force of a suction cup, or sucker is normally used. In this case, in order not to allow the suction cup mark to remain on the silver salt film, the emulsion side of the film must face downward in both the feed and storage magazines 2 and 14. However, when the drum rotation mechanism in FIG. 2 of the above-mentioned Japanese patent application is used in a subscanning section of the apparatus as shown in FIG. 1, this requirement cannot be satisfied.